In a conventional organic light-emitting diode (OLED) display screen, its light-emitting layer is disposed with various metallic signal lines, such as a metallic signal line applied in signal transmission, or a metallic signal line of a switch of a TFT component. But the metallic signal lines can generate reflective light under illumination of external light, the reflective light strongly affects a display effect of the OLED display screen.
To solve the problem, a conventional OLED display screen is covered by a linear polarizer, a ¼ wave plate and top glass from inside to outside on its surface in sequence. As the external light is non-polarized natural light, after the natural light penetrates the linear polarizer, if a transmission axis of the polarizer is along the vertical Y axis, the natural light penetrating the linear polarizer will be converted to be linear polarized light in the Y direction, the linear polarized light subsequently penetrates the ¼ wave plate to be converted to be dextrorotatory rotatory polarized light, the dextrorotatory rotatory polarized light will be converted to be levorotatory rotatory polarized light after reflection of the top glass, the levorotatory rotatory polarized light will be converted to be linear polarized light vibrated along the X direction after being returned by the ¼ wave plate, as the linear polarizer merely permits the light vibrating along Y to pass, polarized light along X will be absorbed by the linear polarizer. The metallic signal line is disposed below the top glass, its reflective light needs to penetrate the top glass and the ¼ wave plate in sequence to reach the linear polarizer, obviously, the reflective light of the metallic signal line cannot be converted to be the linear polarized light vibrated along Y, which is the reflective light generated by the metallic signal line will be absorbed by the linear polarizer, so as to achieve a purpose of eliminating light reflected by the metallic signal line.
Accordingly, the linear polarizer will also absorb light generated by the OLED display screen, as a result, at least half of the optical energy generated by the OLED display screen is absorbed, which reduces luminous efficiency of the OLED display screen significantly.